A few bucks is expensive for auditors (4)
I believe the answer is:
deer
'a few bucks' is the definition.
(I've seen this in another clue)
'expensive for auditors' is the wordplay.
'expensive' becomes 'dear' (similar in meaning).
'for auditors' indicates a 'sounds like' (homophone) clue (auditor can mean someone listening).
'dear' is a homophone of 'DEER'.
'is' is the link.
(Other definitions for deer that I've seen before include "Hoofed grazing animal" , "The male has antlers" , "Grazing animal(s)" , "Eg, stag or doe" , "Like a power switch" .)